1. Field of the Invention
The present invention relates to a technique of presenting a tactile stimulus to a user to notify him/her of information.
2. Description of the Related Art
CPUs having improved throughput and miniaturization of various kinds of devices are accelerating downsizing of general-purpose information terminals represented by a PC and sophistication of mobile information terminals represented by a cellular phone. Even a small single-function device such as a barcode reader behaves as a simple information terminal capable of information operation to some degree by having a high-level information processing function or communication function.
Downsizing information terminals or converting small single-function devices into information terminals enables to widen their use range. However, since the physical size of the information transfer area is small, information input or interpretation of output information is more difficult than before the downsizing or conversion into information terminals. Under these circumstances, how to input or output information without difficulty using a small device has widely been examined.
When visually outputting information, as the information presentation area becomes smaller, the visually output information is harder to recognize, and the efficiency lowers in the nature of the device. A widely known information presentation method oriented to small devices and, more particularly, to handheld devices tactilely presents information. For example, many cellular phones present information of an incoming call or the like by vibration.
According to a technique disclosed in patent reference 1, a plurality of oscillators are attached to a handheld device. The device presents information of a direction by presenting a sense of direction based on a vibration pattern of the oscillators.    [Patent reference 1] Japanese Patent Laid-Open No. 2003-199974
A technique disclosed in patent reference 2 generates a sense of torque using a gyroscope, thereby presenting information of the moving direction of a handheld device.    [Patent reference 2] Japanese Patent Laid-Open No. 2005-100465
Non-patent reference 1 discloses a technique of attaching a plurality of oscillators to the handle of a handheld device and presenting a direction to move the handle by the position of an oscillator that vibrates.    [Non-patent reference 1] Holger Regenbrecht, et al., Virtual Reality Aided Assembly with Directional Vibro-Tactile Feedback, In Proc. GRAPHITE 2005, pp. 381-387, 2005.
Non-patent reference 2 discloses a technique of presenting information of a moving direction by a spurious tractive force generated by a temporally asymmetrical back-and-forth motion of an object.    [Non-patent reference 2] Tomohiro Amemiya, Hideyuki Ando, Taro Maeda, “Perceptual Attraction Force: Exploit the Nonlinearity of Human Haptic Perception”, In Proc. of ACM SIGGRAPH 2006 Sketches, p. 40, Boston, Mass., July 2006.
A tactile stimulus generated by the methods according to these techniques has been put into practical use for information transfer/presentation by small devices in combination with visual information presentation.
However, to use a tactile stimulus for information transfer (information acquisition) in the prior arts, a body part needs to be as supposed in contact with a preset specific portion (stimulus presentation unit) for presenting a stimulus. This may lead to a failure in correctly outputting information to the user depending on how he/she touches the portion.
More specifically, if the body is not in contact with the tactile stimulus presentation unit at all, no information is transferred. If the body is in contact with only part of the stimulus presentation unit, the user recognizes the information wrong.
There can exist a lot of patterns of user's information terminal holding style depending on his/her state or an action to be executed. In the prior arts, however, it is difficult to transfer information to the user while flexibly coping with the various holding styles.